net/netlabel/netlabel_domainhash.c

   1 /*
   2  * NetLabel Domain Hash Table
   3  *
   4  * This file manages the domain hash table that NetLabel uses to determine
   5  * which network labeling protocol to use for a given domain.  The NetLabel
   6  * system manages static and dynamic label mappings for network protocols such
   7  * as CIPSO and RIPSO.
   8  *
   9  * Author: Paul Moore <paul@paul-moore.com>
  10  *
  11  */
  12
  13 /*
  14  * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
  15  *
  16  * This program is free software;  you can redistribute it and/or modify
  17  * it under the terms of the GNU General Public License as published by
  18  * the Free Software Foundation; either version 2 of the License, or
  19  * (at your option) any later version.
  20  *
  21  * This program is distributed in the hope that it will be useful,
  22  * but WITHOUT ANY WARRANTY;  without even the implied warranty of
  23  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
  24  * the GNU General Public License for more details.
  25  *
  26  * You should have received a copy of the GNU General Public License
  27  * along with this program;  if not, write to the Free Software
  28  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  29  *
  30  */
  31
  32 #include <linux/types.h>
  33 #include <linux/rculist.h>
  34 #include <linux/skbuff.h>
  35 #include <linux/spinlock.h>
  36 #include <linux/string.h>
  37 #include <linux/audit.h>
  38 #include <linux/slab.h>
  39 #include <net/netlabel.h>
  40 #include <net/cipso_ipv4.h>
  41 #include <asm/bug.h>
  42
  43 #include "netlabel_mgmt.h"
  44 #include "netlabel_addrlist.h"
  45 #include "netlabel_domainhash.h"
  46 #include "netlabel_user.h"
  47
  48 struct netlbl_domhsh_tbl {
  49         struct list_head *tbl;
  50         u32 size;
  51 };
  52
  53 /* Domain hash table */
  54 /* updates should be so rare that having one spinlock for the entire hash table
  55  * should be okay */
  56 static DEFINE_SPINLOCK(netlbl_domhsh_lock);
  57 #define netlbl_domhsh_rcu_deref(p) \
  58         rcu_dereference_check(p, lockdep_is_held(&netlbl_domhsh_lock))
  59 static struct netlbl_domhsh_tbl *netlbl_domhsh = NULL;
  60 static struct netlbl_dom_map *netlbl_domhsh_def = NULL;
  61
  62 /*
  63  * Domain Hash Table Helper Functions
  64  */
  65
  66 /**
  67  * netlbl_domhsh_free_entry - Frees a domain hash table entry
  68  * @entry: the entry's RCU field
  69  *
  70  * Description:
  71  * This function is designed to be used as a callback to the call_rcu()
  72  * function so that the memory allocated to a hash table entry can be released
  73  * safely.
  74  *
  75  */
  76 static void netlbl_domhsh_free_entry(struct rcu_head *entry)
  77 {
  78         struct netlbl_dom_map *ptr;
  79         struct netlbl_af4list *iter4;
  80         struct netlbl_af4list *tmp4;
  81 #if IS_ENABLED(CONFIG_IPV6)
  82         struct netlbl_af6list *iter6;
  83         struct netlbl_af6list *tmp6;
  84 #endif /* IPv6 */
  85
  86         ptr = container_of(entry, struct netlbl_dom_map, rcu);
  87         if (ptr->def.type == NETLBL_NLTYPE_ADDRSELECT) {
  88                 netlbl_af4list_foreach_safe(iter4, tmp4,
  89                                             &ptr->def.addrsel->list4) {
  90                         netlbl_af4list_remove_entry(iter4);
  91                         kfree(netlbl_domhsh_addr4_entry(iter4));
  92                 }
  93 #if IS_ENABLED(CONFIG_IPV6)
  94                 netlbl_af6list_foreach_safe(iter6, tmp6,
  95                                             &ptr->def.addrsel->list6) {
  96                         netlbl_af6list_remove_entry(iter6);
  97                         kfree(netlbl_domhsh_addr6_entry(iter6));
  98                 }
  99 #endif /* IPv6 */
 100         }
 101         kfree(ptr->domain);
 102         kfree(ptr);
 103 }
 104
 105 /**
 106  * netlbl_domhsh_hash - Hashing function for the domain hash table
 107  * @domain: the domain name to hash
 108  *
 109  * Description:
 110  * This is the hashing function for the domain hash table, it returns the
 111  * correct bucket number for the domain.  The caller is responsible for
 112  * ensuring that the hash table is protected with either a RCU read lock or the
 113  * hash table lock.
 114  *
 115  */
 116 static u32 netlbl_domhsh_hash(const char *key)
 117 {
 118         u32 iter;
 119         u32 val;
 120         u32 len;
 121
 122         /* This is taken (with slight modification) from
 123          * security/selinux/ss/symtab.c:symhash() */
 124
 125         for (iter = 0, val = 0, len = strlen(key); iter < len; iter++)
 126                 val = (val << 4 | (val >> (8 * sizeof(u32) - 4))) ^ key[iter];
 127         return val & (netlbl_domhsh_rcu_deref(netlbl_domhsh)->size - 1);
 128 }
 129
 130 /**
 131  * netlbl_domhsh_search - Search for a domain entry
 132  * @domain: the domain
 133  *
 134  * Description:
 135  * Searches the domain hash table and returns a pointer to the hash table
 136  * entry if found, otherwise NULL is returned.  The caller is responsible for
 137  * ensuring that the hash table is protected with either a RCU read lock or the
 138  * hash table lock.
 139  *
 140  */
 141 static struct netlbl_dom_map *netlbl_domhsh_search(const char *domain)
 142 {
 143         u32 bkt;
 144         struct list_head *bkt_list;
 145         struct netlbl_dom_map *iter;
 146
 147         if (domain != NULL) {
 148                 bkt = netlbl_domhsh_hash(domain);
 149                 bkt_list = &netlbl_domhsh_rcu_deref(netlbl_domhsh)->tbl[bkt];
 150                 list_for_each_entry_rcu(iter, bkt_list, list)
 151                         if (iter->valid && strcmp(iter->domain, domain) == 0)
 152                                 return iter;
 153         }
 154
 155         return NULL;
 156 }
 157
 158 /**
 159  * netlbl_domhsh_search_def - Search for a domain entry
 160  * @domain: the domain
 161  * @def: return default if no match is found
 162  *
 163  * Description:
 164  * Searches the domain hash table and returns a pointer to the hash table
 165  * entry if an exact match is found, if an exact match is not present in the
 166  * hash table then the default entry is returned if valid otherwise NULL is
 167  * returned.  The caller is responsible ensuring that the hash table is
 168  * protected with either a RCU read lock or the hash table lock.
 169  *
 170  */
 171 static struct netlbl_dom_map *netlbl_domhsh_search_def(const char *domain)
 172 {
 173         struct netlbl_dom_map *entry;
 174
 175         entry = netlbl_domhsh_search(domain);
 176         if (entry == NULL) {
 177                 entry = netlbl_domhsh_rcu_deref(netlbl_domhsh_def);
 178                 if (entry != NULL && !entry->valid)
 179                         entry = NULL;
 180         }
 181
 182         return entry;
 183 }
 184
 185 /**
 186  * netlbl_domhsh_audit_add - Generate an audit entry for an add event
 187  * @entry: the entry being added
 188  * @addr4: the IPv4 address information
 189  * @addr6: the IPv6 address information
 190  * @result: the result code
 191  * @audit_info: NetLabel audit information
 192  *
 193  * Description:
 194  * Generate an audit record for adding a new NetLabel/LSM mapping entry with
 195  * the given information.  Caller is responsible for holding the necessary
 196  * locks.
 197  *
 198  */
 199 static void netlbl_domhsh_audit_add(struct netlbl_dom_map *entry,
 200                                     struct netlbl_af4list *addr4,
 201                                     struct netlbl_af6list *addr6,
 202                                     int result,
 203                                     struct netlbl_audit *audit_info)
 204 {
 205         struct audit_buffer *audit_buf;
 206         struct cipso_v4_doi *cipsov4 = NULL;
 207         u32 type;
 208
 209         audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_ADD, audit_info);
 210         if (audit_buf != NULL) {
 211                 audit_log_format(audit_buf, " nlbl_domain=%s",
 212                                  entry->domain ? entry->domain : "(default)");
 213                 if (addr4 != NULL) {
 214                         struct netlbl_domaddr4_map *map4;
 215                         map4 = netlbl_domhsh_addr4_entry(addr4);
 216                         type = map4->def.type;
 217                         cipsov4 = map4->def.cipso;
 218                         netlbl_af4list_audit_addr(audit_buf, 0, NULL,
 219                                                   addr4->addr, addr4->mask);
 220 #if IS_ENABLED(CONFIG_IPV6)
 221                 } else if (addr6 != NULL) {
 222                         struct netlbl_domaddr6_map *map6;
 223                         map6 = netlbl_domhsh_addr6_entry(addr6);
 224                         type = map6->def.type;
 225                         netlbl_af6list_audit_addr(audit_buf, 0, NULL,
 226                                                   &addr6->addr, &addr6->mask);
 227 #endif /* IPv6 */
 228                 } else {
 229                         type = entry->def.type;
 230                         cipsov4 = entry->def.cipso;
 231                 }
 232                 switch (type) {
 233                 case NETLBL_NLTYPE_UNLABELED:
 234                         audit_log_format(audit_buf, " nlbl_protocol=unlbl");
 235                         break;
 236                 case NETLBL_NLTYPE_CIPSOV4:
 237                         BUG_ON(cipsov4 == NULL);
 238                         audit_log_format(audit_buf,
 239                                          " nlbl_protocol=cipsov4 cipso_doi=%u",
 240                                          cipsov4->doi);
 241                         break;
 242                 }
 243                 audit_log_format(audit_buf, " res=%u", result == 0 ? 1 : 0);
 244                 audit_log_end(audit_buf);
 245         }
 246 }
 247
 248 /**
 249  * netlbl_domhsh_validate - Validate a new domain mapping entry
 250  * @entry: the entry to validate
 251  *
 252  * This function validates the new domain mapping entry to ensure that it is
 253  * a valid entry.  Returns zero on success, negative values on failure.
 254  *
 255  */
 256 static int netlbl_domhsh_validate(const struct netlbl_dom_map *entry)
 257 {
 258         struct netlbl_af4list *iter4;
 259         struct netlbl_domaddr4_map *map4;
 260 #if IS_ENABLED(CONFIG_IPV6)
 261         struct netlbl_af6list *iter6;
 262         struct netlbl_domaddr6_map *map6;
 263 #endif /* IPv6 */
 264
 265         if (entry == NULL)
 266                 return -EINVAL;
 267
 268         switch (entry->def.type) {
 269         case NETLBL_NLTYPE_UNLABELED:
 270                 if (entry->def.cipso != NULL || entry->def.addrsel != NULL)
 271                         return -EINVAL;
 272                 break;
 273         case NETLBL_NLTYPE_CIPSOV4:
 274                 if (entry->def.cipso == NULL)
 275                         return -EINVAL;
 276                 break;
 277         case NETLBL_NLTYPE_ADDRSELECT:
 278                 netlbl_af4list_foreach(iter4, &entry->def.addrsel->list4) {
 279                         map4 = netlbl_domhsh_addr4_entry(iter4);
 280                         switch (map4->def.type) {
 281                         case NETLBL_NLTYPE_UNLABELED:
 282                                 if (map4->def.cipso != NULL)
 283                                         return -EINVAL;
 284                                 break;
 285                         case NETLBL_NLTYPE_CIPSOV4:
 286                                 if (map4->def.cipso == NULL)
 287                                         return -EINVAL;
 288                                 break;
 289                         default:
 290                                 return -EINVAL;
 291                         }
 292                 }
 293 #if IS_ENABLED(CONFIG_IPV6)
 294                 netlbl_af6list_foreach(iter6, &entry->def.addrsel->list6) {
 295                         map6 = netlbl_domhsh_addr6_entry(iter6);
 296                         switch (map6->def.type) {
 297                         case NETLBL_NLTYPE_UNLABELED:
 298                                 break;
 299                         default:
 300                                 return -EINVAL;
 301                         }
 302                 }
 303 #endif /* IPv6 */
 304                 break;
 305         default:
 306                 return -EINVAL;
 307         }
 308
 309         return 0;
 310 }
 311
 312 /*
 313  * Domain Hash Table Functions
 314  */
 315
 316 /**
 317  * netlbl_domhsh_init - Init for the domain hash
 318  * @size: the number of bits to use for the hash buckets
 319  *
 320  * Description:
 321  * Initializes the domain hash table, should be called only by
 322  * netlbl_user_init() during initialization.  Returns zero on success, non-zero
 323  * values on error.
 324  *
 325  */
 326 int __init netlbl_domhsh_init(u32 size)
 327 {
 328         u32 iter;
 329         struct netlbl_domhsh_tbl *hsh_tbl;
 330
 331         if (size == 0)
 332                 return -EINVAL;
 333
 334         hsh_tbl = kmalloc(sizeof(*hsh_tbl), GFP_KERNEL);
 335         if (hsh_tbl == NULL)
 336                 return -ENOMEM;
 337         hsh_tbl->size = 1 << size;
 338         hsh_tbl->tbl = kcalloc(hsh_tbl->size,
 339                                sizeof(struct list_head),
 340                                GFP_KERNEL);
 341         if (hsh_tbl->tbl == NULL) {
 342                 kfree(hsh_tbl);
 343                 return -ENOMEM;
 344         }
 345         for (iter = 0; iter < hsh_tbl->size; iter++)
 346                 INIT_LIST_HEAD(&hsh_tbl->tbl[iter]);
 347
 348         spin_lock(&netlbl_domhsh_lock);
 349         rcu_assign_pointer(netlbl_domhsh, hsh_tbl);
 350         spin_unlock(&netlbl_domhsh_lock);
 351
 352         return 0;
 353 }
 354
 355 /**
 356  * netlbl_domhsh_add - Adds a entry to the domain hash table
 357  * @entry: the entry to add
 358  * @audit_info: NetLabel audit information
 359  *
 360  * Description:
 361  * Adds a new entry to the domain hash table and handles any updates to the
 362  * lower level protocol handler (i.e. CIPSO).  Returns zero on success,
 363  * negative on failure.
 364  *
 365  */
 366 int netlbl_domhsh_add(struct netlbl_dom_map *entry,
 367                       struct netlbl_audit *audit_info)
 368 {
 369         int ret_val = 0;
 370         struct netlbl_dom_map *entry_old;
 371         struct netlbl_af4list *iter4;
 372         struct netlbl_af4list *tmp4;
 373 #if IS_ENABLED(CONFIG_IPV6)
 374         struct netlbl_af6list *iter6;
 375         struct netlbl_af6list *tmp6;
 376 #endif /* IPv6 */
 377
 378         ret_val = netlbl_domhsh_validate(entry);
 379         if (ret_val != 0)
 380                 return ret_val;
 381
 382         /* XXX - we can remove this RCU read lock as the spinlock protects the
 383          *       entire function, but before we do we need to fixup the
 384          *       netlbl_af[4,6]list RCU functions to do "the right thing" with
 385          *       respect to rcu_dereference() when only a spinlock is held. */
 386         rcu_read_lock();
 387         spin_lock(&netlbl_domhsh_lock);
 388         if (entry->domain != NULL)
 389                 entry_old = netlbl_domhsh_search(entry->domain);
 390         else
 391                 entry_old = netlbl_domhsh_search_def(entry->domain);
 392         if (entry_old == NULL) {
 393                 entry->valid = 1;
 394
 395                 if (entry->domain != NULL) {
 396                         u32 bkt = netlbl_domhsh_hash(entry->domain);
 397                         list_add_tail_rcu(&entry->list,
 398                                     &rcu_dereference(netlbl_domhsh)->tbl[bkt]);
 399                 } else {
 400                         INIT_LIST_HEAD(&entry->list);
 401                         rcu_assign_pointer(netlbl_domhsh_def, entry);
 402                 }
 403
 404                 if (entry->def.type == NETLBL_NLTYPE_ADDRSELECT) {
 405                         netlbl_af4list_foreach_rcu(iter4,
 406                                                    &entry->def.addrsel->list4)
 407                                 netlbl_domhsh_audit_add(entry, iter4, NULL,
 408                                                         ret_val, audit_info);
 409 #if IS_ENABLED(CONFIG_IPV6)
 410                         netlbl_af6list_foreach_rcu(iter6,
 411                                                    &entry->def.addrsel->list6)
 412                                 netlbl_domhsh_audit_add(entry, NULL, iter6,
 413                                                         ret_val, audit_info);
 414 #endif /* IPv6 */
 415                 } else
 416                         netlbl_domhsh_audit_add(entry, NULL, NULL,
 417                                                 ret_val, audit_info);
 418         } else if (entry_old->def.type == NETLBL_NLTYPE_ADDRSELECT &&
 419                    entry->def.type == NETLBL_NLTYPE_ADDRSELECT) {
 420                 struct list_head *old_list4;
 421                 struct list_head *old_list6;
 422
 423                 old_list4 = &entry_old->def.addrsel->list4;
 424                 old_list6 = &entry_old->def.addrsel->list6;
 425
 426                 /* we only allow the addition of address selectors if all of
 427                  * the selectors do not exist in the existing domain map */
 428                 netlbl_af4list_foreach_rcu(iter4, &entry->def.addrsel->list4)
 429                         if (netlbl_af4list_search_exact(iter4->addr,
 430                                                         iter4->mask,
 431                                                         old_list4)) {
 432                                 ret_val = -EEXIST;
 433                                 goto add_return;
 434                         }
 435 #if IS_ENABLED(CONFIG_IPV6)
 436                 netlbl_af6list_foreach_rcu(iter6, &entry->def.addrsel->list6)
 437                         if (netlbl_af6list_search_exact(&iter6->addr,
 438                                                         &iter6->mask,
 439                                                         old_list6)) {
 440                                 ret_val = -EEXIST;
 441                                 goto add_return;
 442                         }
 443 #endif /* IPv6 */
 444
 445                 netlbl_af4list_foreach_safe(iter4, tmp4,
 446                                             &entry->def.addrsel->list4) {
 447                         netlbl_af4list_remove_entry(iter4);
 448                         iter4->valid = 1;
 449                         ret_val = netlbl_af4list_add(iter4, old_list4);
 450                         netlbl_domhsh_audit_add(entry_old, iter4, NULL,
 451                                                 ret_val, audit_info);
 452                         if (ret_val != 0)
 453                                 goto add_return;
 454                 }
 455 #if IS_ENABLED(CONFIG_IPV6)
 456                 netlbl_af6list_foreach_safe(iter6, tmp6,
 457                                             &entry->def.addrsel->list6) {
 458                         netlbl_af6list_remove_entry(iter6);
 459                         iter6->valid = 1;
 460                         ret_val = netlbl_af6list_add(iter6, old_list6);
 461                         netlbl_domhsh_audit_add(entry_old, NULL, iter6,
 462                                                 ret_val, audit_info);
 463                         if (ret_val != 0)
 464                                 goto add_return;
 465                 }
 466 #endif /* IPv6 */
 467         } else
 468                 ret_val = -EINVAL;
 469
 470 add_return:
 471         spin_unlock(&netlbl_domhsh_lock);
 472         rcu_read_unlock();
 473         return ret_val;
 474 }
 475
 476 /**
 477  * netlbl_domhsh_add_default - Adds the default entry to the domain hash table
 478  * @entry: the entry to add
 479  * @audit_info: NetLabel audit information
 480  *
 481  * Description:
 482  * Adds a new default entry to the domain hash table and handles any updates
 483  * to the lower level protocol handler (i.e. CIPSO).  Returns zero on success,
 484  * negative on failure.
 485  *
 486  */
 487 int netlbl_domhsh_add_default(struct netlbl_dom_map *entry,
 488                               struct netlbl_audit *audit_info)
 489 {
 490         return netlbl_domhsh_add(entry, audit_info);
 491 }
 492
 493 /**
 494  * netlbl_domhsh_remove_entry - Removes a given entry from the domain table
 495  * @entry: the entry to remove
 496  * @audit_info: NetLabel audit information
 497  *
 498  * Description:
 499  * Removes an entry from the domain hash table and handles any updates to the
 500  * lower level protocol handler (i.e. CIPSO).  Caller is responsible for
 501  * ensuring that the RCU read lock is held.  Returns zero on success, negative
 502  * on failure.
 503  *
 504  */
 505 int netlbl_domhsh_remove_entry(struct netlbl_dom_map *entry,
 506                                struct netlbl_audit *audit_info)
 507 {
 508         int ret_val = 0;
 509         struct audit_buffer *audit_buf;
 510
 511         if (entry == NULL)
 512                 return -ENOENT;
 513
 514         spin_lock(&netlbl_domhsh_lock);
 515         if (entry->valid) {
 516                 entry->valid = 0;
 517                 if (entry != rcu_dereference(netlbl_domhsh_def))
 518                         list_del_rcu(&entry->list);
 519                 else
 520                         RCU_INIT_POINTER(netlbl_domhsh_def, NULL);
 521         } else
 522                 ret_val = -ENOENT;
 523         spin_unlock(&netlbl_domhsh_lock);
 524
 525         audit_buf = netlbl_audit_start_common(AUDIT_MAC_MAP_DEL, audit_info);
 526         if (audit_buf != NULL) {
 527                 audit_log_format(audit_buf,
 528                                  " nlbl_domain=%s res=%u",
 529                                  entry->domain ? entry->domain : "(default)",
 530                                  ret_val == 0 ? 1 : 0);
 531                 audit_log_end(audit_buf);
 532         }
 533
 534         if (ret_val == 0) {
 535                 struct netlbl_af4list *iter4;
 536                 struct netlbl_domaddr4_map *map4;
 537
 538                 switch (entry->def.type) {
 539                 case NETLBL_NLTYPE_ADDRSELECT:
 540                         netlbl_af4list_foreach_rcu(iter4,
 541                                              &entry->def.addrsel->list4) {
 542                                 map4 = netlbl_domhsh_addr4_entry(iter4);
 543                                 cipso_v4_doi_putdef(map4->def.cipso);
 544                         }
 545                         /* no need to check the IPv6 list since we currently
 546                          * support only unlabeled protocols for IPv6 */
 547                         break;
 548                 case NETLBL_NLTYPE_CIPSOV4:
 549                         cipso_v4_doi_putdef(entry->def.cipso);
 550                         break;
 551                 }
 552                 call_rcu(&entry->rcu, netlbl_domhsh_free_entry);
 553         }
 554
 555         return ret_val;
 556 }
 557
 558 /**
 559  * netlbl_domhsh_remove_af4 - Removes an address selector entry
 560  * @domain: the domain
 561  * @addr: IPv4 address
 562  * @mask: IPv4 address mask
 563  * @audit_info: NetLabel audit information
 564  *
 565  * Description:
 566  * Removes an individual address selector from a domain mapping and potentially
 567  * the entire mapping if it is empty.  Returns zero on success, negative values
 568  * on failure.
 569  *
 570  */
 571 int netlbl_domhsh_remove_af4(const char *domain,
 572                              const struct in_addr *addr,
 573                              const struct in_addr *mask,
 574                              struct netlbl_audit *audit_info)
 575 {
 576         struct netlbl_dom_map *entry_map;
 577         struct netlbl_af4list *entry_addr;
 578         struct netlbl_af4list *iter4;
 579 #if IS_ENABLED(CONFIG_IPV6)
 580         struct netlbl_af6list *iter6;
 581 #endif /* IPv6 */
 582         struct netlbl_domaddr4_map *entry;
 583
 584         rcu_read_lock();
 585
 586         if (domain)
 587                 entry_map = netlbl_domhsh_search(domain);
 588         else
 589                 entry_map = netlbl_domhsh_search_def(domain);
 590         if (entry_map == NULL ||
 591             entry_map->def.type != NETLBL_NLTYPE_ADDRSELECT)
 592                 goto remove_af4_failure;
 593
 594         spin_lock(&netlbl_domhsh_lock);
 595         entry_addr = netlbl_af4list_remove(addr->s_addr, mask->s_addr,
 596                                            &entry_map->def.addrsel->list4);
 597         spin_unlock(&netlbl_domhsh_lock);
 598
 599         if (entry_addr == NULL)
 600                 goto remove_af4_failure;
 601         netlbl_af4list_foreach_rcu(iter4, &entry_map->def.addrsel->list4)
 602                 goto remove_af4_single_addr;
 603 #if IS_ENABLED(CONFIG_IPV6)
 604         netlbl_af6list_foreach_rcu(iter6, &entry_map->def.addrsel->list6)
 605                 goto remove_af4_single_addr;
 606 #endif /* IPv6 */
 607         /* the domain mapping is empty so remove it from the mapping table */
 608         netlbl_domhsh_remove_entry(entry_map, audit_info);
 609
 610 remove_af4_single_addr:
 611         rcu_read_unlock();
 612         /* yick, we can't use call_rcu here because we don't have a rcu head
 613          * pointer but hopefully this should be a rare case so the pause
 614          * shouldn't be a problem */
 615         synchronize_rcu();
 616         entry = netlbl_domhsh_addr4_entry(entry_addr);
 617         cipso_v4_doi_putdef(entry->def.cipso);
 618         kfree(entry);
 619         return 0;
 620
 621 remove_af4_failure:
 622         rcu_read_unlock();
 623         return -ENOENT;
 624 }
 625
 626 /**
 627  * netlbl_domhsh_remove - Removes an entry from the domain hash table
 628  * @domain: the domain to remove
 629  * @audit_info: NetLabel audit information
 630  *
 631  * Description:
 632  * Removes an entry from the domain hash table and handles any updates to the
 633  * lower level protocol handler (i.e. CIPSO).  Returns zero on success,
 634  * negative on failure.
 635  *
 636  */
 637 int netlbl_domhsh_remove(const char *domain, struct netlbl_audit *audit_info)
 638 {
 639         int ret_val;
 640         struct netlbl_dom_map *entry;
 641
 642         rcu_read_lock();
 643         if (domain)
 644                 entry = netlbl_domhsh_search(domain);
 645         else
 646                 entry = netlbl_domhsh_search_def(domain);
 647         ret_val = netlbl_domhsh_remove_entry(entry, audit_info);
 648         rcu_read_unlock();
 649
 650         return ret_val;
 651 }
 652
 653 /**
 654  * netlbl_domhsh_remove_default - Removes the default entry from the table
 655  * @audit_info: NetLabel audit information
 656  *
 657  * Description:
 658  * Removes/resets the default entry for the domain hash table and handles any
 659  * updates to the lower level protocol handler (i.e. CIPSO).  Returns zero on
 660  * success, non-zero on failure.
 661  *
 662  */
 663 int netlbl_domhsh_remove_default(struct netlbl_audit *audit_info)
 664 {
 665         return netlbl_domhsh_remove(NULL, audit_info);
 666 }
 667
 668 /**
 669  * netlbl_domhsh_getentry - Get an entry from the domain hash table
 670  * @domain: the domain name to search for
 671  *
 672  * Description:
 673  * Look through the domain hash table searching for an entry to match @domain,
 674  * return a pointer to a copy of the entry or NULL.  The caller is responsible
 675  * for ensuring that rcu_read_[un]lock() is called.
 676  *
 677  */
 678 struct netlbl_dom_map *netlbl_domhsh_getentry(const char *domain)
 679 {
 680         return netlbl_domhsh_search_def(domain);
 681 }
 682
 683 /**
 684  * netlbl_domhsh_getentry_af4 - Get an entry from the domain hash table
 685  * @domain: the domain name to search for
 686  * @addr: the IP address to search for
 687  *
 688  * Description:
 689  * Look through the domain hash table searching for an entry to match @domain
 690  * and @addr, return a pointer to a copy of the entry or NULL.  The caller is
 691  * responsible for ensuring that rcu_read_[un]lock() is called.
 692  *
 693  */
 694 struct netlbl_dommap_def *netlbl_domhsh_getentry_af4(const char *domain,
 695                                                      __be32 addr)
 696 {
 697         struct netlbl_dom_map *dom_iter;
 698         struct netlbl_af4list *addr_iter;
 699
 700         dom_iter = netlbl_domhsh_search_def(domain);
 701         if (dom_iter == NULL)
 702                 return NULL;
 703
 704         if (dom_iter->def.type != NETLBL_NLTYPE_ADDRSELECT)
 705                 return &dom_iter->def;
 706         addr_iter = netlbl_af4list_search(addr, &dom_iter->def.addrsel->list4);
 707         if (addr_iter == NULL)
 708                 return NULL;
 709         return &(netlbl_domhsh_addr4_entry(addr_iter)->def);
 710 }
 711
 712 #if IS_ENABLED(CONFIG_IPV6)
 713 /**
 714  * netlbl_domhsh_getentry_af6 - Get an entry from the domain hash table
 715  * @domain: the domain name to search for
 716  * @addr: the IP address to search for
 717  *
 718  * Description:
 719  * Look through the domain hash table searching for an entry to match @domain
 720  * and @addr, return a pointer to a copy of the entry or NULL.  The caller is
 721  * responsible for ensuring that rcu_read_[un]lock() is called.
 722  *
 723  */
 724 struct netlbl_dommap_def *netlbl_domhsh_getentry_af6(const char *domain,
 725                                                    const struct in6_addr *addr)
 726 {
 727         struct netlbl_dom_map *dom_iter;
 728         struct netlbl_af6list *addr_iter;
 729
 730         dom_iter = netlbl_domhsh_search_def(domain);
 731         if (dom_iter == NULL)
 732                 return NULL;
 733
 734         if (dom_iter->def.type != NETLBL_NLTYPE_ADDRSELECT)
 735                 return &dom_iter->def;
 736         addr_iter = netlbl_af6list_search(addr, &dom_iter->def.addrsel->list6);
 737         if (addr_iter == NULL)
 738                 return NULL;
 739         return &(netlbl_domhsh_addr6_entry(addr_iter)->def);
 740 }
 741 #endif /* IPv6 */
 742
 743 /**
 744  * netlbl_domhsh_walk - Iterate through the domain mapping hash table
 745  * @skip_bkt: the number of buckets to skip at the start
 746  * @skip_chain: the number of entries to skip in the first iterated bucket
 747  * @callback: callback for each entry
 748  * @cb_arg: argument for the callback function
 749  *
 750  * Description:
 751  * Interate over the domain mapping hash table, skipping the first @skip_bkt
 752  * buckets and @skip_chain entries.  For each entry in the table call
 753  * @callback, if @callback returns a negative value stop 'walking' through the
 754  * table and return.  Updates the values in @skip_bkt and @skip_chain on
 755  * return.  Returns zero on success, negative values on failure.
 756  *
 757  */
 758 int netlbl_domhsh_walk(u32 *skip_bkt,
 759                      u32 *skip_chain,
 760                      int (*callback) (struct netlbl_dom_map *entry, void *arg),
 761                      void *cb_arg)
 762 {
 763         int ret_val = -ENOENT;
 764         u32 iter_bkt;
 765         struct list_head *iter_list;
 766         struct netlbl_dom_map *iter_entry;
 767         u32 chain_cnt = 0;
 768
 769         rcu_read_lock();
 770         for (iter_bkt = *skip_bkt;
 771              iter_bkt < rcu_dereference(netlbl_domhsh)->size;
 772              iter_bkt++, chain_cnt = 0) {
 773                 iter_list = &rcu_dereference(netlbl_domhsh)->tbl[iter_bkt];
 774                 list_for_each_entry_rcu(iter_entry, iter_list, list)
 775                         if (iter_entry->valid) {
 776                                 if (chain_cnt++ < *skip_chain)
 777                                         continue;
 778                                 ret_val = callback(iter_entry, cb_arg);
 779                                 if (ret_val < 0) {
 780                                         chain_cnt--;
 781                                         goto walk_return;
 782                                 }
 783                         }
 784         }
 785
 786 walk_return:
 787         rcu_read_unlock();
 788         *skip_bkt = iter_bkt;
 789         *skip_chain = chain_cnt;
 790         return ret_val;
 791 }